h1 {
    font-size: 1.2em;
    color: #999;
    margin-bottom: 0;
}

h2 {
    font-size: 2em;
    margin-top: 0;
    padding-top: 0;
    color: blueviolet;
    text-align: center
}

nav {
    margin: auto;
    display: block;
    width: 30%;
}

nav a {
    padding: 5px 10px 5px 10px;
    text-decoration: none;
    display: inline-block;
    border-radius: 4px;
    margin-top: 2em;
    margin-left: 2em;
}

//访问过得样式
// nav a:visited {
//     background-color: #eee;
// }
//正常，未访问过的链接
nav a:visited,
a:link {
    background-color: #efefef;
    color: #607d8b;
    cursor: pointer;
}

//当有鼠标悬停在其上的链接样式
nav a:hover {
    color: #039be5;
    background-color: #92999c;
    cursor: pointer;
}

//当你点击链接时的样式
nav a.active {
    color: #039be5;
    background-color: aqua;
    cursor: pointer;
}